--  @testpoint:opengauss关键字preferred(非保留)，作为函数名

--关键字不带引号-成功
drop function if exists preferred;
create function preferred(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
drop function preferred;
--关键字带双引号-成功
drop function if exists "preferred";
create function "preferred"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
drop function "preferred";
--关键字带单引号-合理报错
drop function if exists 'preferred';
create function 'preferred'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--关键字带反引号-合理报错
drop function if exists `preferred`;
create function `preferred`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/